The real safety feature of these is to inflate them underwater and acend with them above you to keep the mororns in jetskis and bass boats from wacking you as you ascend. Mine is the nylon cloth model with a mouth inflate, but I can manage to inflate it underwater by mouth (takes some practice and not necessarily recommended). I only inflate about half filled when 15 feet from the surface, then ascend holding the bottom and slowly rise up, so that if a boat is coming at you, they hopefully see the orange thing coming up while your arm is still 6 feet under. This puts your head (a critical piece of equipment if there ever was one) about 8 feet under as the tube emerges. Take note though, the expanding air in this thing is going to make you slightly more bouyant, and filling it by mouth could be troublesome to a few folks. If you use a signal tube in this way, you want to get some practice with it and be sure you can manage the increased bouyancy as you ascend. In addition to a safety sausage, a high piercing whistle is recommended and takes up no room at all. A whistle can be heard through fog and rain , wheareas a sausage can only be seen in good weather.